Pulp-digester



IINTTE STATES FATE T OFFICE.

GEORGE E. RUSSELL, OF LAWRENCE, MASSACHUSETTS.

PU LP-DIGESTER.

SPECIFICATION forming part of Letters Patent No. 445,235, dated January 2'7, 1891.

Application filed October 18, 1890. Serial No. 368,558- (No model.)

To all whom it may concern.-

Be it known that I, GEORGE F. RUssELL, of Lawrence, in the county of Essex and State of lllassachusetts, a citizen of the United States, have invented certain new and useful Improvements in Pulp-Digesters, of which the following is a specification.

My invention relates to improvements in the construction of the vessels ordinarily called digesters, in which wood pulp is manufactured by what is known as the sulphite process.

Its object is to improve the construction of these digesters so as to prevent their injury by the solution employed.

In the accompanying drawing I have represented in vertical section a pulp-digester of a well known form, commonly called the Globe Rotary. The shell of the digester is marked A, and within it are shown linings l3 and (I, the construction whereof I will now proceed to describe.

A represents the outer shell of the digester. it. is ordinarily constructed of metal, such as iron, steel, or brass, which is liable to be injuriously affected by the acid solution employed. Upon the interior of the shell of the digester I form a continuous lining or coat B of acidresist-ing material applied in a plastic condition. This lining or coat is of the nature of a cement, and may be composed of any material or mixture of materials which is acidresisting and capable of being made plastic and adhesive to the shell of the digester. A convenient material for the purpose is commercial cement, preferably Portland, made plastic with water and applied with anysuitable implement upon the interior of the digester-shell, so as to form a continuous covering therefor. Other cement-like materials or mixtures having similar properties or characteristics may be used, such as the ordinary cement mixtures, sand and Portland cement, sand and tar, and the like.

Under some circumstances it will be found in practice that the friction of the mass of pulp within the digester, particularly when of the rotary pattern, is likely to mechanically wear away the lining constructed as described. This objectionable feature may be remedied by setting an inner lining C of tiles upon the continuous lining B, the plasticity and adhesiveness of which may be utilized to hold the tiles in place. In many cases, however, the use of this inner lining of tiles will not be found necessary.

\Vhile I have represented but one form of digester in the drawing, it will be understood that my improvement is not confined to that form alone, but is of general application.

I am aware of the use heretofore of a digester-liniug comprising a layer or coat of masonry or brick-work laid in cement, and make no claim thereto. Such linings I believe to be objectionable, in that they are heavy and require in many forms of digester special forms of tile or brick to be constructed to fit various portions of the digester-shell, especially around openings, (to. Furthermore, they are expensive by reason of requiring to be laid or constructed with great care and skill to prevent defective joints through which leakage may take place. On the other hand, in a digester embodying my improvement the lining may be applied rapidly and easily, and may be composed of material not necessarily expensive. Again, it has been customary to supplement the brick or tile linings heretofore in use with a lining of sheet-lead interposed between the brick or tile lining and the digester-shell. This feature may be entirely dispensed with where my improvement is adopted.

I claim 1. The improved pulp-digester herein described, having an outer shell A and a continuous lining or coat B of cement, as described, applied to the interior of the said shell, for the purpose set forth.

2. The improved pulp-digester herein described, having an outer shell A, a continuous lining or coat B of cement, substantially as described, applied to the interior of the said shell, and ap inner lining of tiles O, all substantially as set forth.

In testimony whereof I have hereunto subscribed my name this Sd day of October, A. D. 1890.

GEORGE 1?. RUSSELL.

Witnesses:

JOHN II. TAYLOR, ELLEN B. TOMLINSON. 

